Another limitation of OT is its inability to compare measures defined on two distinct spaces.
This is for instance the case when comparing different graphs [1]}, [2]} or in genomics when the measurements are performed using distinct modalities [3]}.
Section  details a variant of OT called Gromov-Wasserstein (GW) which circumvents this issue, at the expense of solving a much more difficult (in particular non-convex) optimization problem.
